William Goetzmann

William Goetzmann is a professor at Yale's School of Management who studies the history of financial markets and behavioral finance. His 2016 book "Money Changes Everything: How Finance Made Civilization Possible" traced the development of financial instruments from ancient Mesopotamia through the modern era, arguing that finance has been central to human social development rather than merely extractive. He has also developed long-horizon capital market data sets and contributed research on the equity premium, survivorship bias, and bubbles in historical perspective. His construction of multi-century equity return series — incorporating data from early Dutch and British markets alongside the longer US record — has been critical to evaluating whether the 20th century US equity premium was representative of what investors should expect globally, or whether survivorship bias from focusing on the most successful capital market in history distorts expectations. His empirical analysis of historical bubble episodes — using statistical criteria to identify price run-ups and reversals across centuries — provided systematic evidence that financial bubbles have been a recurring feature of market economies rather than a modern anomaly.